Supercooled surgical instrument



United States Patent 72] Inventor Max L. Hirschhorn 3,398,738 8/1968Lamb et al l28/303.1 3 hA B kl N Y k No ew or Primary Examiner-L. W.Trapp [2 1 pp No 736 529 Attorney-l enneth S. Goldfarb 22 Filed June 12,1968 Patented 24, 1970 ABSTRACT: A supercooled surgical instrumentcomprising a [54] SUPERCOOLED SURGICAL INSTRUMENT heat conductivesurgical tool having a hollow thin walled body of heat conductivematerial of low icing capacity and a thermally insulative handleconnected to the body. A reservoir containing a cryogenic liquidincluding means for injecting a precooled nontoxic inert gas into thecryogenic liquid so that the said gas and said liquid are supercooled byexpansion during passage through the cryogenic liquid, and outlet meanslocated above the liquid level of the cryogenic liquid for removing thesupercooled gas from the reservoir is interconnected with the bodythrough means disposed in the handle of the tool or by venting said gasalong the outer contour of the instrument in order to increase thecooling of the instrument and to prevent icing by repelling the watermolecules of the surrounding air.

1 I- 40 32 1- -L i H 44 'Pate'ntd ov. 24, 1970' 3,5 2,029

Sheet 2 Orz- INVENTOR. MAX L. H/RSCl/HORN 1' SUPERCOOLEDSURGICAL'INSTRUMENT reducing its localmetabolic needs. Generally, in thepast surgery has been performed using knives, probes, biopsy scoops andother instruments which are applied directly to-body tissue, thetemperature of the tissue having been lowered by external means, forexample, by application of ethyl chloride to the skin to freeze it byevaporation general area of the local surgery.

. Until now the use of surgical instruments for cutting or prior toincision in the i piercing body tissue having been subjected to localfreezing I was limitedby the fact that the instrument adhered to thecooled flesh at the point of incision. In order to remove the in--strument from the cooled flesh without causing severe damage tosurrounding tissue it was necessary to heat the instrument, for example,by heating coils located in its interior. Therefore, the use of suchsurgical instruments were restricted to a single cutting motion, thenwaiting for a lengthy period for renewed deep cooling of the bladebefore continuing with-the opera tion. The blade would be coveredwithice'andbe insufficient since it would not have a clean cutting edge ifrenewed deep cooling were not allowed'and after the initial incision wasmade, resortwas had to cohventional'implements for continu ous surgicalmovements.

Under certain circumstances the necessity of performing" the majorportion of the operation with conventional surgical instruments isparticularly disadvantageous. In the case of cancer surgery, an attemptto selectively remove cancerous tissue is'not without danger oftransmitting the cancer cells to the blood stream and thereafter toother areas of the'body by way of the circulatory system. In likemanner, surgery of infected areas may cause subsequent spread ofinfection .organ-' isms andcapillary'bleedingjislikewise prevented.

v The surgical technique requiring p'reliminarycooling of the-- mentwhich may be removably'mou'nted into the end of a hanbody is beset withmany problems. Some'of these difficulties stem from the fact thatthereis no way of controlling the temperature of the flesh at any giventime during the operative procedure due to .the rapid rate at which heatis exchanged between theambient and the portion of the body beingoperated upon. 7

It is therefore a primary object of the present invention to provide -asurgical instrument having a cutting edge or tool which maybe accuratelyand continuously cooled below ambient room temperature, wherein thedegree of cooling can be closely controlled at all times during thesurgical procedure.

The cooled edge acts to reduce the localbody tissue metabolism at thepoint of and immediately surrounding the'area of incision therebyreducing the local bleeding and v spread of .cancer cells or otherinfecting organisms to the circulatory system, at the same time itmodifies the metabolicrate of local tissues to a degree of totaldestruction if so desired.

.It is still another'object of this inventiontoprovide a supercooledsurgical instrumentwhich can move and sever body tis- H sue at thesurgeons desired speed of movement,,cooling being of the surgicalimplement shown in FIG. 10.

continuously applied by the body of the instrument to the body tissue.

It is a further object of this invention to provide a super cooledsurgical instrument which can easily be maintained at a substantiallyuniform temperature throughout the entire surgi cal process, thesurgical instrument beingmaintained at a temperature so lowas'to-render' thesurgical instrumentselfsterilizing. i

It is also an object ofthis invention to provide a coolable surgicalinstrumentjhaving means to constantly control the temperature ofthe'ambient proximate to the area being operated upon.

It is still another object of the present invention to provide asurgical instrument, which instrument is constructed from thermallyconductive material which will not adhere to the body'tissue beingpenetrated by it or closely situated to the incised area at the requiredtemperature.

Another object of this invention resides in the provision of a surgicalinstrument having a handle which is thermally insulated by novelinsulation materials.

In accordance with the aforesaid objects of the invention a supercooledsurgical instrument is provided having a body portion cooled by anexternal or internal cryogenic cooling system. A plurality of thermallyconductive surgical tools and implements may be removably inserted intothe end of the handle. Preferably, the body or handle portion isprovided with a temperaturesensing and control apparatus so that thetemperature of the surgical tools and implements may be predeterminedand maintained constant.

Other objects and features of the present invention will become apparentas the following description proceeds, several preferred embodiments ofwhich have been illustrated in the accompanying drawings, wherein:

FIG. 1 is a diagrammatic view of one embodiment of the surgicalinstrument in accordance with the concepts of the present. inventionshowing the manner in which a plurality of surgical tools are externallyconnected to a source of cryogenic cooling and temperature controlpanel;

FIG. 1a is a diagramatic view of a second embodiment of the surgicalinstrument in which the surgical tools are externally connected to asource of cryogenic liquid and'temperature control panel;

FIG. 2 is a vertical sectional view of the source of cryogenic coolingshown in FIG. 1;

FIG. 3 is a perspective view of a surgical tool in accordance with thepresent invention;

FIG. 4 is an enlarged detailed longitudinal sectional view of thesurgical tool illustrated in FIG..3 showing the manner in whichthe toolis connected to the cryogenic cooling system and the internal circuitryfor monitoring the temperature of the tool;

FIG. 5 is a fragmentary top plan view of a surgical impledle inaccordance with the concepts of the present invention;

FIG. 5a is a fragmentary top plan view of a modified version of thesurgical implement shown in FIG. 5;

FIG. 6 is a perspective view of another surgical tool in accordance withthe concepts of this invention;

FIG. 7 is an enlarged detailed longitudinal sectional view of thesurgical tool illustrated by FIG. 6 showing an internal cryogeniccooling system disposed within the handle and body of the tool;

FIG. 8 is a fragmentary side elevational view of a surgical implementwhich may be removably mounted into the end of the handle of thesurgical instrument.

- FIG. 9 is a fragmentary top plan view of another surgical imp lementwhich may be removably mounted into the end of the handle;

FIG. 10 is a perspective side view of a further surgical implement whichmay be removably mounted into the end of the handle; and

FIG. 11 is a detailed fragmentary longitudinal sectional view Withcontinuing reference to the accompanying drawings, whereinlike referencenumerals designate similar parts throughout the various views, referencenumeral 20 is used to generally designate the surgical tool of thepresent invention. In one embodiment of the invention the surgical tool20 is connected to a source of cryogenic cooling'22 and a temperaturesensing and control panel 24. The surgical tool 20 includes a body 26having at least one honed cutting edge 28 or -a piercing member, forexample, the needle 30 illustrated in FIGS. 10 and 11, which may beremovably inserted into a thermally insulative handle 32. The source ofcryogenic cooling 22 comprises an insulated reservoir 34 containing acryogenic liquid 36, a conduit 38 for injecting a precooled nontoxicinert gas into the cryogenic liquid contained in the reservoir andanother tube or conduit located above the liquid level of the cryogenicliquid for removal of supercooled gas. In one embodiment of thisinvention a gas compression pump and/or gas flow regulator generallyindicated at 42 is disposed between gas injection conduit or inlet 38and gas removal conduit or outlet 40 for recycling and condensingsupercooled gas, thereby increasing the efficiency of the coolingsystem. There may also be provided a temperature control panel 24 whichmonitors the temperature of the body portion 26 of surgical tool 20 bymeans of a temperature sensing device 44, for example, a thermistor (seeFIG. 4) or thermocouple embedded close to the outside surface of body26. The cooling system of this invention may be readily adapted to coolmore than one surgical tool at a time, as for example the pair ofimplements 20 and 44 shown in FIG. 1.

The source of cryogenic cooling 22 operates by injection of a precooledinert gas through conduit 38 into a cryogenic liquid in which the inertgas is insoluble or only very slightly soluble, i.e. the gas bubblesthrough the liquid at an accelerating rate, the gas molecules movingaway from one another and occupying a greater volume with a concurrentincrease in the size of the bubbles. Although no attempt is made here toexplain the resulting cooling effect of the passage of the gas throughthe liquid, the expansion of the gas bubbles decreases the vaporpressure of the gas within the bubbles so that molecules of liquidhaving above average kinetic energies evaporate into the gas bubbles,thereby extracting heat from the liquid and cooling the liquid. If it isdesired to utilize the supercooled gas without subsequent recyclingthrough compression pumps 22, the liquid may be replenished throughconduit 46.

The cryogenic liquid may be any nonexplodable, nontoxic, low molecularweight substance. Of those substances meeting the aforementionedrequirements, the choice of liquid will depend upon the temperature atwhich the surgeon chooses to perform the operation. Typically, thesetemperatures will be in the range of about 63K. to about 200K. Preferredcryogenic liquids are: nitrogen (freezing point, 63.3K.; boiling point,77.4K.) and freon l4 (freezing point, 128K.; boil ing point, ll(.). Dryice'sublimes at 194.7.'K. and may be utilized in place ofa cryogenicliquid.

The supercooled gas leaves the reservoir through conduit 40 which passesthrough handle of the surgical tool 20 and then into an evaporatingchamber 48 formed by hollow thin walled body 26. Vents 50 and 52 areprovided for removal of supercooled gas from evaporating chamber 48. Ifdesired the surgical implement may be vented in other manners, as inFIG. 8, where a plurality of vents 54 are located in the top or in FIG.9 where a single vent 56 is located in the body. It should be noted thatvents 50 and 52 permit the supercooled gas to circulate around thecontour of the body on which they are located thereby controlling thetemperature of the ambient immediately surrounding area of incision.Therefore, it is preferable that the gas have a low heat capacity. Sincethe supercooled gases come into contact with body tissue they must benontoxic as well as insoluble or only slightly soluble in the cryogenicliquid or other cryogenic substance, such as has been previouslymentioned. It is possible to use any inert gas meeting the aboverequirements, although helium is preferred.

Although certain ambients can rapidly absorb heat, the rate oftransference of heat or cold through such mediums is very slow.Therefore, it is necessary in the instant invention to operate at verylow temperatures. Furthermore, the surgical implement itself must, inaddition to being a good thermal conductor, have as small a thermal massas possible to permit rapid heat exchange with the ambient and formaximum efficiency.

This invention further provides the novel use of sapphire and zirconiumoxide or materials having similar physical characteristics from whichthe body of the surgical tool is fabricated. Desirably, sapphire andzirconium oxide are extremely hard, are excellent thermal conductors,and are electrically nonconductive. Electrical nonconductivity rendersthe use of these materials particularly attractive since there is noelectrical discharge which would injure the body tissue being operatedupon. In some cases this might even be fatal. Equally important is thefactthat sapphire and zirconium oxide surgical implements will notfreeze into the incised area even at the very low temperatures beingused in this invention.

The handle of the surgical tool utilizes a novel form of insulationmaterial. The material is manufactured by superposing several layers ofplastic material, such as polystyrene, upon one another. The superposedlayers are heated in a vacuum chamber, causing the layers toincompletely join because of low pressure vacuoles created at theinterfaces of successive layers, thereby forming an unevenly constructedwafer. Not only do such materials exhibit very poor thermalconductivity, but they also have great tensile strength. Moreover, theelasticity of the material will help to maintain the low atmosphericpressure within the vacuoles. This material is particularly useful incryogenic applications because of the severely low temperaturesinvolved.

It is also desired that the temperature of the body of the surgical toolbe controllable. For this purpose a thermistor 44 or thermocouple, noshown, may be embedded at the interface of the body wall and theevaporating chamber. Suitably the thermistor may be made from sapphire.The thermistor 44 is connected to a wire 58 which passes through thehandle 32 of the instrument. From the handle the wire passes to controlpanel 24 where by means of various temperature reading gauges thetemperature can be monitored. Thus, the flow of gas into conduit 38 andflow of liquid into conduit 46 can be regulated to achieve any desiredtemperature. If it is desired that the surgeon be constantly advised ofthe temperature at which he is working and oscillator 62 may beconnected to the panel 24. Alternatively, an amber light 64 may beincorporated in the panel or on the handle, as indicated in FIG. 6,which will light up when the temperature of the body of the surgicalinstrument has reached its present value.

FIG. la illustrates a preferred embodiment of the invention. Cryogenicliquid travels from a source, not shown, through a conduit 46 whichpasses through a thermally insulated handle 32 of the surgical tool 20.As the liquid approaches the tip of conduit 46 which communicates withthe hollow chamber of a body 26 in all respects identical to the body ofFIG. 4, it instantaneously evaporates, concurrently supercooling thebody of the tool. The gas may either be vented, as previously described,or be recycled through a compression pump 42. Temperature monitoringmeans disposed within the body may be conveniently connected by a wire58 to a temperature control panel 24.

In another embodiment of the invention, illustrated in FIGS. 6 and 7, athermally insulative handle 66 which communicates with a body 72 in sucha manner that handle 66 and body 72 jointly form a reservoir for thecryogenic liquid. Gas inlet tubes 68 pass into the interior of thehandle 66 and inject cryogenic liquid which may be continuouslyreplenished through inlet 70. A thermistor 74 is disposed at theinterface of the body wall with reservoir chamber 79 and is connected bya wire 76 to an amber light 64 and finally to a temperature controlpanel 24. Supercooled gas may be removed from evaporating chamber 78through gas outlet tubes 80 or 82, illustrated by FIGS. 6 and 7,respectively. The gas may then be recycled through a compression pump,not shown, or merely permitted to escape into the atmosphere.

FIGS. 5 and 5a relate to a further important teaching of this inventionand consists of a jet stream arrangement of the supercooled gasesventing from the surgical scalpel downward along the sides of theinstrument causing the H 0 molecules in the approximate air space to bedispelled and thus tending to prevent additionally the condensation ofwater vapor upon the instrument or icing. The inert cooled gases can beforced through the vents by very high pressure at an acute angle. Thegas .streams would meet and join forces a very short distance from thecutting edge of the instrument. The gas stream would then assume adownward direction. Such cooled air stream will cool anddestroythetissues in a linear fashion before the confluence pattern. Thereservoir does not necessarily possess a cutting edge and may beconstructed of any suitable material.

' 'This embodiment will eminently serve for cutting bone cartilage andgive alladvantage of controlled freezing.

More particularly-with reference to FIG; 5, there is pro-' videda-surgical implement having a tapered hollow body 27, tip 41 .andcutting edge 43. The body is provided with cryogenicfluid inlet tubes 29for cryogenic liquid and/or gas so that when inert ,gas is passed intothe cryogenic liquid, the.

gas and liquid become'supercooled. Supercooled inert gas is removedfromthe body at vents 31.and 33 designed to permit the vented gas totravel along the tapered contours of the body and meet at a point 39 inadvance of the tip 41- of the implement. The pressure of the'supercooled. gas vented from the body is regulated by jet control valves35 and 37 located at vents 31 and 33 at avalue on the order of 0.25 atm.The supercooled gas stream will cool the air proximate to the tip 41 ofthe implement and cool and destroy body tissues in a linearfashionbefore the cutting edge 43 of the supercooled implement reachesthebody tissue. The supercooled gas stream will also substantiallyminimize condensation of tissue fluid and tend to prevent the cuttingblade of the instrument from freezing into severed tissues. i

in the embodiment depicted in FIG. a"the hollow body 57 has a blunt tip45 The vents 47 and 49, including jet control valves 51 and 53,areregulated. to direct inert gas to flow amiund the body contours, theinert gas stream meeting in advance of tip'45 at apointisfi'lhe gasstream is controlled at a substantially; greater pressure (-for;example, multiples of 0.25

and in a manner consistent-with the spirit and scope of the inventionherein.

- um gas jet striking down in an acute angle in a linear or pointlclaim: 1. A supercooled surgical instrument comprising a heatconductive surgical tool having a hollow thin walled body of heatconductive material selected from the class of materials consisting ofsapphire and zirconium mode, a thermally insulative handle connected tosaid body, a reservoir containing a cryogenic liquid, means forinjecting a precooled nontoxic inert gas into said cryogenic liquid insaid reservoir so that said gas is supercooled by expansion duringpassage through said including reinforcing means for rigidifying theinterior of said body,-said means being a thin layer of thermallyconductive material. t

3. A supercooled surgical instrument according to claim 1, wherein athermally responsive means is embedded in said body for monitoring thetemperature of said body.

I 4. A supercooled surgical instrument according to claim 3. whereinsaid thermally responsive means is a sapphire thermistor. I

t 5. A'supercooled surgical instrument according to'claim 1, whereinsaid body is provided with outlet means for removing said'supe'rcooledgas from said body, and outlet means being located above the liquidlevel of said cryogenic liquid in said body, and compression pump meansfor recycling said supercooled gas to said handle.

6. A supercooled surgical instrument according to claim I, wherein saidbody is provided with vent means for removal of said supercooled gas.

'7. A supercooledsurgical instrument according to claim 6, wherein saidreservoir includes inlet means for replenishing saidcryogenic liquid insaid reservoir.

A supercooled surgical instrument according to claim 7, whereinsaid ventmeans direct supercooled gas along the outw side contours of said body.

atr'n.)'than in the embodiment shown in FIG. S'pe'rmitting the inert gasstreamto cut bone or cartilage as it strikes the tissue in a linear orpoint confluence pattern.

FIGS. 10 and '11. depict a further surgical implement according tothisirivention. Needle or piercing implement 84;is

connected to a handle, not shown, and to a source of cryogenic liquid bya conduit 100 located at the base of the implement and a lengthofsurgical thread 98 passing through an aperture located .in the endwall 90 of the implement.- Cryogenic- .liquid which flows'into the gasevaporating chamber 96-through conduit 100 is evaporated as hereinbefore described jand may be vented at outlet 100.

- is further contemplated by this invention toreinforce the I interiorof hollow'thin walled sapphire or zirconium oxide with 9,. Asupercooledsurgical instrument according to claim 1,

whereinsaid handle and said-bodyare interconnected to jointly form saidreservoir, said means for injecting said gas being located in saidhandle.

10. An apparatus for supercooling bodies comprising a v reservoircontaining a cryogenic liquid, means for injecting a A latitude of modifcation, substitution and 'change is intended in the foregoingdisclosure, and in some instances some features of thepresent'invention' may be employed without a corresponding use ofotherfeatures. Accordingly, it

precooled nontoxic inert gas into said cryogenic liquid in saidreservoir so that said gas and said cryogenic liquidare supercooled byexpansion of said gas during passage through said cryogenic liquid, saidreservoir having outlet means located above the liquid level of saidcryogenic liquid for removing the supercooled-gas from said reservoir,and means for interconnecting a body to be supercooled with said outletmeans.

11. A supercooled surgical instrument comprising a heat conductivesurgical tool having a hollow thin walled body, a

' thermally insulative handle connected to said body, a reservoircontaining a cryogenic fluid disposed in the body of said tool, meansfor injecting-a precooled nontoxic inert gas into said cryogenic fluidin said reservoir so that said gas is supercooled-by expansion duringpassage through said cryogenic fluid thereby supercooling said cryogenicfluid, and means on said body communicating with said reservoir fordirecting flow of supercooled'gas outwardly of said body and in a pathsub stantially conforming to the contours of said body so that saidgases meet in advance of said body.

